1. Translated by Mrs. L. A., Bauer, , in Terrestrial Magnetism, , vol. IV, , 1899, , pp. 73– -86 . (“The beginnings of magnetic observations.”)
2. Wolkenhauer, A., , Beiträge zur Geschichte der Kartographic und Nautik des 15. bis. 17, . Jahrhunderts Inaug. Diss. Un. Göttingen, , Munich, (F. Straub), 1904, . Pp. 80 and 12 figs.
3. Über die Kenntniss der magnetischen Deklination vor Christoph Columbus;Hellmann;Meteorol. Z. S.,1906
4. Originally given in the “ United States Magnetic Declination Tables for 1902, , and Principal Facts Relating to the Earth's Magnetism, by L. A., Bauer, , , Washington, , 1902, .
5. This value is given on a map by Dudley, R., , in the “Areano del Mare,” and preserved by Petrus Koerius, dated 1646, showing the coast of New Albion, discovered by Sir F. Drake in 1579. Narrative and critical history of America, , Justin Winsor, , , II, , Boston and New York, , 1886, .